title: Preparation and evaluation of a novel glass-ionomer cement with antibacterial functions.
abstract: OBJECTIVE
  The objective of this study was to use the newly synthesized poly(quaternary ammonium salt) (PQAS)-containing polyacid to formulate the light-curable glass-ionomer cements and study the effect of the PQAS on the compressive strength and antibacterial activity of the formed cements.
  
  
  METHODS
  The functional QAS and their constructed PQAS were synthesized, characterized and formulated into the experimental high-strength cements. Compressive strength (CS) and Streptococcus mutans viability were used to evaluate the mechanical strength and antibacterial activity of the cements. Fuji II LC cement was used as control. The specimens were conditioned in distilled water at 37°C for 24 h prior to testing. The effects of the substitute chain length, loading as well as grafting ratio of the QAS and aging on CS and S. mutans viability were investigated.
  
  
  RESULTS
  All the PQAS-containing cements showed a significant antibacterial activity, accompanying with an initial CS reduction. The effects of the chain length, loading and grafting ratio of the QAS were significant. Increasing chain length, loading, grafting ratio significantly enhanced antibacterial activity but reduced the initial CS. Under the same substitute chain length, the cements containing QAS bromide were found to be more antibacterial than those containing QAS chloride although the CS values of the cements were not statistically different from each other, suggesting that we can use QAS bromide directly without converting bromide to chloride. The experimental cement showed less CS reduction and higher antibacterial activity than Fuji II LC. The long-term aging study suggests that the cements may have a long-lasting antibacterial function.
  
  
  CONCLUSIONS
  This study developed a novel antibacterial glass-ionomer cement. Within the limitations of this study, it appears that the experimental cement is a clinically attractive dental restorative due to its high mechanical strength and antibacterial function.
authors.affiliation: Department of Biomedical Engineering, Purdue School of Engineering and Technology, Indiana University-Purdue University at Indianapolis, Indianapolis, IN 46202, USA. dxie@iupui.edu
authors.forename: Dong
authors.initials: D
authors.lastname: Xie
authors.forename: Yiming
authors.initials: Y
authors.lastname: Weng
authors.forename: Xia
authors.initials: X
authors.lastname: Guo
authors.forename: Jun
authors.initials: J
authors.lastname: Zhao
authors.forename: Richard L
authors.initials: RL
authors.lastname: Gregory
authors.forename: Cunge
authors.initials: C
authors.lastname: Zheng
mesh_terms: D000643:Ammonium Chloride / Q000737:chemistry; D000900:Anti-Bacterial Agents / Q000138:chemical synthesis / Q000737:chemistry*; D001965:Bromides / Q000737:chemistry; D019245:Compressive Strength; D004126:Dimethylformamide / Q000737:chemistry; D004852:Epoxy Compounds / Q000737:chemistry; D005899:Glass Ionomer Cements / Q000138:chemical synthesis / Q000737:chemistry*; D006801:Humans; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry; D008826:Microbial Sensitivity Tests; D050296:Microbial Viability / Q000187:drug effects; D008968:Molecular Conformation; D018583:Pliability; D011108:Polymers / Q000737:chemistry; D000644:Quaternary Ammonium Compounds / Q000737:chemistry; D012117:Resins, Synthetic / Q000737:chemistry; D013295:Streptococcus mutans / Q000187:drug effects; D013314:Stress, Mechanical; D013696:Temperature; D013718:Tensile Strength; D013997:Time Factors; D014867:Water / Q000737:chemistry
chemical_list: D000900:Anti-Bacterial Agents; D001965:Bromides; D004852:Epoxy Compounds; C079765:Fuji II LC cement; D005899:Glass Ionomer Cements; D008689:Methacrylates; D011108:Polymers; D000644:Quaternary Ammonium Compounds; D012117:Resins, Synthetic; D000643:Ammonium Chloride; D014867:Water; C008219:itaconic-acrylic acid copolymer; D004126:Dimethylformamide; C051470:ammonium bromide; C007870:glycidyl methacrylate